Views: 932     Author: Site Editor     Publish Time: 2020-03-05      Origin: Site

Dryer refers to a kind of mechanical equipment which uses heat energy to reduce moisture content of materials, and is used for drying objects. Do you know the working principle of the dryer?


The amount of water vapor in compressed air is determined by the temperature of compressed air. While keeping the pressure of compressed air basically unchanged, reducing the temperature of compressed air can reduce the content of water vapor in compressed air. And excess water vapor will condense into liquid. The freeze dryer uses this principle to use refrigeration technology to dry compressed air. Therefore, the cold dryer has a refrigeration system.

The refrigeration system of the freeze dryer is a compression type refrigeration system consisting of four basic components: a refrigeration compressor, a condenser, an evaporator, and an expansion valve. They are connected in series by pipes to form a closed system in which the refrigerant circulates continuously in the system, undergoes state changes and exchanges heat with cooling medium.


The refrigeration compressor draws the low-pressure (low-temperature) refrigerant in the evaporator into the cylinder of the compressor,. The refrigerant vapor is compressed, and the pressure and temperature are simultaneously increased. The high-pressure high-temperature refrigerant vapor is pressed to the condenser. And in the condenser, the higher temperature refrigerant vapor exchanges heat with the cooler water or air. The heat of the refrigerant is taken away by water or air, and the refrigerant vapor becomes a liquid. This part of the liquid is then transported to the expansion valve, through the expansion valve throttle into low-temperature and low-pressure liquid and into the evaporator; in the evaporator, low-temperature and low-pressure refrigerant liquid absorbs the heat of compressed air and vaporizes, while compressed air is cooled and condenses a large amount of liquid water. The refrigerant vapor in the evaporator is sucked away by the compressor again, so that the refrigerant undergoes four processes of compression, condensation, throttling, and evaporation in the system, thereby Completed a loop.

In the refrigeration system of the freeze dryer, the evaporator is a device for conveying a cold amount, in which the refrigerant absorbs the heat of the compressed air to achieve the purpose of dehydration and drying. The compressor is like the heart, which plays the role of inhaling, compressing and transporting refrigerant vapor. Condenser is a device that emits heat. The heat absorbed in the evaporator is transferred to the cooling medium (such as water or air) along with the heat converted by the input power of the compressor. The expansion valve/throttle valve acts as a throttle to reduce the pressure of the refrigerant, simultaneously controls and regulates the amount of refrigerant liquid flowing into the evaporator, and divides the system into two parts, a high pressure side and a low pressure side.


The future development of the industrial dryer will be in-depth study of the drying mechanism and material drying characteristics, mastering the optimal operating conditions for different materials, developing and improving the dryer. In addition, large-scale, high-strength, high-economic, and improved adaptability to raw materials and product quality are the basic trends in the development of industrial dryers.


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